RE: [Sip] B2BUA & Max-Forwards

[Juan-Carlos.Rojas@alcatel.fr]

Hello,

As it was already stated in this discusion thread, a B2BUA is an
*application* linking several UAs
As such, the behaviour of a B2BUA cannot be standardised.

Therefore, one cannot say that "A B2BUA needs to propagate some of the
headers received".
However, you can say that the application "x" behaves as a B2BUA, and that
the application "x" "needs to propagate" the a-header or the b-header etc.
for the needs of the application. This is the choice of the application,
that's all.

Best regards
Juan Carlos





Adam Roach <adam@dynamicsoft.com>@ietf.org on 04/12/2002 01:36:50

Sent by:  sip-admin@ietf.org


To:   "'Padma Suresh'" <padma_suresh@hotmail.com>, vkg@lucent.com,
      pete@tech-know-ware.com
cc:   sip@ietf.org
Subject:  RE: [Sip] B2BUA & Max-Forwards


-----Original Message-----
From: Padma Suresh [mailto:padma_suresh@hotmail.com]

> A B2BUA needs to propagate some of the headers received in a
> request/response to the other endpoint. Example: Require...

No. As emphatically as possible: NO. This is completely wrong,
and it appears to be a growing -- and dangerous -- misconception.

A B2BUA cannot transparently pass Require through. It must
understand and invoke the extension indicated.

  "The Require header field contains a list of option tags, described in
   Section 19.2.  Each option tag defines a SIP extension that MUST be
   understood to process the request."

A back to back user agent *is* a UAS, and *is* bound by this
provision.

Whether the UAC portion then turns around and imposes the same
requirement on the UAS it contacts is a local decision.

/a
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_______________________________________________
Sip mailing list  https://www1.ietf.org/mailman/listinfo/sip
This list is for NEW development of the core SIP Protocol
Use sip-implementors@cs.columbia.edu for questions on current sip
Use sipping@ietf.org for new developments on the application of sip